Preheat oven to 180°C/350°F/Gas 4. Mix tomatoes, olives, garlic, capers, onion and oil in a roasting tin and season. Roast for 35 minutes. Stir in chicken and roast for 10 minutes, or until chicken is just cooked through.

Stir in spinach and cook for 2–3 minutes until wilted. Check seasoning.